Solution for adding iptables firewall policy to MySQL service

[root@mysql ~]# firewall-cmd --state
running

[root@mysql ~]# systemctl stop firewalld.service

[root@mysql ~]# firewall-cmd --state
not running

[root@mysql ~]# systemctl start firewalld.service

[root@mysql ~]# systemctl enable firewalld.service

[mysql@mysql ~]$ mysql -utony -ptony -h 192.168.112.131 -P 3306
mysql: [Warning] Using a password on the command line interface can be insecure.
ERROR 2003 (HY000): Can't connect to MySQL server on '192.168.112.131' (113)

Master-slave replication connection test [root@localhost] 15:23:46 [(none)]>show slave status\G;
*************************** 1. row ***************************
               Slave_IO_State: Connecting to master
                  Master_Host: 192.168.112.131
                  Master_User: repl
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: binlog.000034
          Read_Master_Log_Pos: 194
               Relay_Log_File:mysql-relay-bin.000007
                Relay_Log_Pos: 401
        Relay_Master_Log_File: binlog.000034
             Slave_IO_Running: Connecting
            Slave_SQL_Running: Yes
           .....
Master_SSL_Verify_Server_Cert: No
                Last_IO_Errno: 2003
                Last_IO_Error: error connecting to master '[email protected]:3306' - retry-time: 60 retries: 1
               Last_SQL_Errno: 0

[root@mysql ~]# iptables -L -n --line-number|grep 3306

[mysql@mysql ~]$ mysql -utony -ptony -h 192.168.112.131 -P 3306
mysql: [Warning] Using a password on the command line interface can be insecure.
ERROR 2003 (HY000): Can't connect to MySQL server on '192.168.112.131' (113)

# iptables -I INPUT -p tcp -m state --state NEW -m tcp --dport 3306 -j ACCEPT
[root@mysql ~]# iptables -L -n --line-number|grep 3306
1 ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:3306

[root@mysql ~]# iptables -D INPUT 1
[root@mysql ~]# iptables -L -n --line-number|grep 3306